Roller crushing-mill for ores.



No. 779,045.' PATLNTLD JAN. 3, 1905. G.JOHNSTON.

ROLLER GRUSHING MILL FOR URLS.

APPLICATION FILED MAY 24, 1904.

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PATENT OFFICE.

GEORGE JOHNSTON, OF SAN FRANCISCO, CALIFORNIA.

ROLLER CRUSHlNG-NIILL FOR CRES.

SPECIFICATION forming part of Letters Patent No. 779,045, dated January 3, 1905.

Application filed May 24, 1904:. Serial No. 209,584.

T car/ZZ whom/ t may concern:

Beit known that I, GEORGE JOHNSTON, a citizen of the United States of-America, residing at San Francisco, county of San Francisco, and

State of California, have invented certain new and useful Improvements in Roller Crushing- Mills for Orcs; and I hereby declare the following to be a full, clear, and exact description of and to certain useful improvements whereby their efficiency is increased.

My improvements consist in a fixed hollow standard around which the crushing-rollers revolve, which standard forms an inlet or supply-way for ore, is bolted rmly to the base-frame,and maintains the crushing-rollers in a concentric path.

The objects of my invention are to secure a uniform -action of the crushing-rollers all around their path and insure the complete passage of the ore across this path, and thereby increase the efciency of the crushingrollers and the quality of the work to be performed.

To these ends I construct crushing-machines as shown in the drawings herewith and forming a part of this specification.

Figure I is an elevation, mainly in section, of atriple-roller crushing-machine constructed according to my invention with the plural charging-inlets for ore situated within the path of the rollers. Fig. II is a section on the line t a in Fig. I, showing the base of the hollow standard and the inlet-ways for ore.

In the operation of roller crushing-machines of the Chilian type there are commonly employed two or more heavy rollers set on edges to roll about a central driving-shaft and act on the material, that when reduced to a certain degree of ineness is washed outward and escapes radially through a series of selectingscreens. In such arrangement of parts a step and usually other bearings are disposed below the crushing-level of the ore and exposed to sand and grit. Also the ore has to be supplied either around the periphery of the pan or from the interior through chutes that revolve about the center of the pan and deliver in the path of the rollers.

It is discovered that when the broken ore is supplied 'at a fixed point or points in respect to the rollers and directly within the path thereof the work performed is not so rapid and efficient as where the material is supplied from the center outward and falls into the most open spaces b y gravity. Also as an essential feature the whole of the material must cross the whole width of the die-ring 3 before being discharged outward through the screens. It is thus found by experiment that by employing devices to supply the ore around the machine at several stationary points within the die-ring the effect becomes nearly uniform, the screens discharging alike and the vworking result much increased in both quantity and quality. To attain this result, I employ the means and apparatus now to be described by the aid of the drawings, that illustrate an application of my invention.

Referring to Fig. I of the drawings, 1 is the pan or main frame, 2 crushing-rollers, and 3 the die-ring on which they bear. 4L is an oscillatory frame on which the rollers 2 are mounted; 5, a driving member connected to the frame 4 by the pins 7, that slide loosely in the member 5. The screens are not shown in the drawings` but are a well-known feature not entering into the present claim. The inember 5 is driven by the bevel gear-wheel 8 attached at 9, a pinion 10, and shaft 11, supported in a frame 12, the latter being keyed to a fixed hollow su pporting-stem 13, as shown in the drawings.

The central hollow supporting-stem 13, which constitutes a main feature, is flanged at the bottom and firmly bolted down to the base, as shown in Fig. I, and besides forming a lateral support for the operating parts becomes also aconduit for the ore and water supplied to the machine. The hollow form of this central stem 13 greatly increases its rigidity with the same mass, and the ore is delivered centrally in the machine in the most desirable position and below all running joints liable to abrasion bysand.

The central bore or passage 17 in the standard 13 is made large enough to pass freely the broken ore 18, which is supplied at the top IOO through a spout l5, set in an angular position to clear the shaft 11, and on reaching the bottom the ore ows by gravity out through the apertures 14.

From the passages or inlet-ways 14 in the bottom of the hollow standard 13 the ore 18 is by disturbance of the rollers 2 and wash of' the water contained in the pan l gradually caught between the rollers 2 and the die-ring at the inner side, so that all the ore must cross the full width of the path of the rollers before being discharged outward through the screenways.

I am aware that crushing-rollers of the Ohilian type have been guided and sustained by a fixed central standard, and that in other machines the ore-supply has been distributed in the path of the crushing-rollers and from the center of such machines. I do not, therefore, claim either of these features separately; but

to this specification in the presence of two sub-- scribing witnesses.

GEORGE JOHNSTON.

, Witnesses:

HENRY C. DROGER, ELMER WIoKEs. 

